My father the car salesman used to say "The people that think they are smart are the easiest to fool."
That is why I think they are gullible.
And their theory being, "How smart can you be if you are a car salesman." Thus they believe they are in the 'driver seat' in terms of knowledge which leads to the "of course you want the best undercoating and chrome molly keniblet pins?" "Why yes, of course I do."

" I see you know your stuff, I won't even charge you the normal delivery fee but don't let my manager know." They now become like butter.
